Abstract：
Bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae (Xoo), poses a significant threat to rice cultivation across diverse regions. Growing concerns about pesticide resistance and environmental impact underscore the urgent necessity for eco-friendly biopesticides. Here, the complete genome sequence of Streptomyces albidoflavus strain ML27 revealed substantial antimicrobial activity and secondary metabolite production potential through genome mining. 3,4-dimethoxyphenol (purity 97%) was successfully isolated from the fermentation broth of S. albidoflavus strain ML27, exhibiting broad and pronounced inhibitory effects on the growth of seven different fungi and five tested bacteria. The efficacy of 3,4-dimethoxyphenol in controlling rice bacterial leaf blight was evaluated through pot tests, demonstrating substantial therapeutic (69.39%) and protective (84.53%) effects. Application of 3,4-dimethoxyphenol to Xoo resulted in cells displayed notable surface depressions, wrinkles, distortions, or even ruptures compared to their typical morphology. Transcriptome analysis revealed significant inhibition of membrane structures, protein synthesis and secretion, bacterial secretion system, two-component system, flagellar assembly, as well as various metabolic and biosynthetic pathways by 3,4-dimethoxyphenol. Notably, the down-regulation of the type III secretion system (T3SS) expression was a pivotal finding. Furthermore, validation via quantitative real-time polymerase chain reaction (qRT-PCR) analysis confirmed significant downregulation of 10 genes related to T3SS upon 3,4-dimethoxyphenol treatment. Based on these results, it is promising to develop 3,4-dimethoxyphenol as a novel biopesticide targeting the T3SS of Xoo for controlling bacterial leaf blight in rice.
摘要：
细菌性叶枯病，由米黄单胞菌pv引起。稻米（Xoo），对不同地区的水稻种植构成重大威胁。对农药抗性和环境影响的日益关注突显了对生态友好型生物农药的迫切需要。这里,白黄链霉菌ML27菌株的完整基因组序列通过基因组挖掘揭示了大量的抗菌活性和次生代谢产物潜力.3,4-二甲氧基苯酚（纯度97％）成功地从S.albidofavus菌株ML27的发酵液中分离得到，对7种不同真菌和5种测试细菌的生长表现出广泛而明显的抑制作用。通过盆栽试验评价了3,4-二甲氧基苯酚防治水稻细菌性叶枯病的效果,表现出实质性的治疗作用（69.39%）和保护作用（84.53%）。将3,4-二甲氧基苯酚应用于Xoo导致细胞显示出明显的表面凹陷，皱纹,扭曲，甚至与它们的典型形态相比破裂。转录组分析显示膜结构受到显著抑制，蛋白质合成和分泌，细菌分泌系统，双组分系统，鞭毛组装，以及3,4-二甲氧基苯酚的各种代谢和生物合成途径。值得注意的是,III型分泌系统(T3SS)表达下调是一个关键发现.此外，通过定量实时聚合酶链反应（qRT-PCR）分析进行的验证证实，在3,4-二甲氧基苯酚处理后，与T3SS相关的10个基因显着下调。基于这些结果,有望开发3,4-二甲氧基苯酚作为一种针对Xoo的T3SS的新型生物农药，用于控制水稻细菌性叶枯病。
